Switch assembly



Sept- 11, 1962 w. B. PONSOT ET AL 3,053,951

SWITCH ASSEMBLY Filed Feb, 8, 1960 5 Sheets-Sheet', 1

Agay

Sept 11, 1962 w. B. PoxNso-r ETAL 3,053,951

SWITCH ASSEMBLY 3 Sheets-Sheet 2 Filed Feb. 8, 1960 Sept. 11, 1962w.B.Po1NsoT ETAL 3,053,951

SWITCH ASSEMBLY Filed Feb. 8, 1960 5 Sheets-Sheet 3 Filed Feb. 8, 1960,Ser. No. 7,389 19 Claims. (Cl. Zilli-90) This invention relates to aswitch assembly in which a plurality of magnetically operated switchesare mounted to extend into an annular air gap and to be swept by tlux inthe air gap so as to provide successive and periodic operations of theswitches. The invention is more particularly directed to an improvedswitching assembly of this type which is quite small and compact and inwhich the switches operate at precisely timed intervals.

Switching assemblies which are capable of operating at extremely highswitching rates at precisely timed intervals iind wide utility in theelectronic and electric arts. A number of such switching assemblies aredisclosed in co-pending patent applications tiled in the name of GlennA. Reese. These applications include the applications Serial No.652,968, tiled April 15, 1957 (now Patent 2,945,931), Serial No.656,051, tiled April 30, 1957 (now Patent 2,932,699), Serial No.753,041, tiled August 4, 1958, and Serial No. 813,736, filed May 18,1959. In these co-pending patent applications, a plurality ofmagnetically operated switches are mounted to extend into an annular airgap. A magnetic flux is produced throughout the annular air gap andslight tiux distortions are introduced at predetermined angularpositions around the annular air gap. The components which form theannular air gap and the components including magnets which produce thelinx in the air gap are mounted on a rotor which is rotated with respectto the magnetically operated switches. The switches are axially mountedin alignment with the longitudinal axis of the rotor at a predetermineddistance therefrom. The ux distortions, which are due to theconfiguration of the rotor, are swept lsuccessively past the magneticswitches to provide for this operation. The switches are extremelysensitive and are operated by slight distortions of the tlux in theannular air gap.

In each of the above-identied patent applications, the switches areaxially aligned, being in alignment with the longitudinal axis of therotor. In order to provide for the successive operation of the switches,the switches are spaced apart so that such assemblies are bulky whenrelatively large numbers of switches are utilized. These assemblies arebulky also because the flux pattern, which is rotated adjacent theswitches, is developed by magnets in the rotor. The magnets place alimitation as to how small the rotor can be made.

In a copending patent application, tiled on even date herewith in thename of Glenn A. Reese, a compact switching assembly of high timingaccuracy is provided which occupies less than 25 percent of the volumeof the prior switching assemblies. The switches are radially instead ofaxially disposed with respect to the axis of rotation of the rotor andextend into an annular groove in the rotor. The rotor is made ofmagnetic material with the magnets utilized to develop the magneticfield through the annular air gap being included as part of the stator.The rotor, without permanent magnets is made quite small. Due to theradial alignment of the switches and the utilization of a magnet freerotor, a more compact assembly is provided and any one of the switchesof a stacked assembly arrangement may readily be removed withoutdecoupling the individual assemblies.

In an illustrative embodiment of this invention, a compact radial switchassembly is provided which is an I, ntedf SrateS atent improvement ofthe assembly disclosed in the patent application tiled on even dateherewith. With the switches radially disposed, a small axial movement ofthe rotor varies the switching interval of each of the plurality ofmagnetically operated switches by a considerable factor. For example, inthe illustrative embodiment, the switches may be operated duringsuccessive channels or intervals of 1750 microseconds. An axial movementof the rotor of one hundredth (0.01) of an inch varies the switchinginterval in one direction or the other by 400 microseconds. Features ofthis invention relate to the provision of means for maintaining a timingaccuracy in the presence of axial movements of the rotor.Illustratively, the switching interval varies by less than microsecondsfor axial rotor movements of 0.020 inch.

The timing accuracy is maintained utilizing a double rotor assemblyhaving an outer and an inner rotor each including two rings of magneticmaterial. The two rotors are concentric, with the two rings of eachrotor together forming the annular air gap in which the magneticswitches are radially disposed. The annular air gap is formed throughboth rotors. One ring in each rotor forms at least one tongue andadjacent thereto the other ring forms a groove. The tongue and grooveproduce flux distortions for operating the switches. Both rotors havethe tongues and grooves at the same angular position but the positionsof the tongue and groove are reversed being on opposite rings of the tworotors.

The magnetic circuit, which is developed by magnets in the stator,passes through the tongue of one rotor, through the armature of a switchto the tongue of the other rotor. Any axial displacement of the rotorsincreases the air gap adjacent one tongue and decreases it adjacent theother tongue so that the total reluctance of the magnetic circuitremains the same. Utilizing the double rotor, the operating duration ofa switch and its timing position in the operating cycle of the switchingassembly are essentially constant. Moreover, the switching interval foroperating each switch is at a minimum. The doub-le rotor assembly has anadditional advantage in that variations in the construction of themagnetic switches are effectively normalized. The exact alignment of thearmature of the switch is not critical.

Further features of this invention pertain to the provision of a pair ofsteel segments adjacent each of the magnetic switches to effectivelypulse the adjacent switch with a steep wave front pulse responsive todistortions of the flux in the annular air gap. The shape of the wavefront is independent of the axial position of the rotor. The steelsegments, in this manner, assist the double rotor in maintaining thetiming accuracy with axial displacements of the rotor.

Still further features of this invention pertain to provision of groovesin one ring of each rotor which are wider than the tongues in the otherring of each rotor. The steel segments move fully adjacent a groovebefore coming adjacent the associated tongue. ln this manner, the uxthrough one ring of a rotor fully disperses before the flux from theother ring is introduced to the segments.

The utilization of a double rotor provides for forces at the oppositeends of the armature in the magnetic switches as the tongues and groovesrotate adjacent the armatures. Further features of this invention relateto the utilization of magnetic switches having armatures which arepivoted at their centers so that the forces at the opposite ends of thearmature are both effective in facilitating its rapid movement.

Further advantages and features of this invention will become apparentupon consideration of the following description when read in conjunctionwith the drawing, wherein:

FIGURE 1 is a perspective view of a bank of switching assemblies of thisinvention and of a motor and gear box utilized to dnive the switchingassemblies;

FIGURE 2 is an exploded perspective view of the stator and rotorutilized in the switching assembly of this invention;

FIGURE 3 is a partially sectionalized perspective view of the switchingassembly of this invention with a portion of the stator and rotorremoved;

FIGURE 4 is a partial sectional view of the switching assembly of thisinvention in a plane perpendicular to the longitudinal axis of the rotorand stator of the switching assembly of this invention;

FIGURE 5 is a sectional View of the switching assembly of this inventiontaken along lines 5 5 in FIG- URE 4 illustrating the spacing of themagnetic switches;

FIGURE 6 is a sectional view through one of the magnetic switchesutilized in the switching assembly of this invention;

FIGURE 7 is a sectional View of a portion of another embodiment of amagnetic switch which is utilized in the switching assembly of thisinvention;

FIGURE 8 is a sectional View taken along lines 8 3 of FIGURE 6illustrating the relationship of the armature contact and stationarysegment contacts of the magnetic switch utilized in the assembly of thisinvention;

FIGURES 9a, 9b `and 9c are schematic representations of the air gapformed by the double rotor of the switching assembly of this invention,wherein:

FIGURE 9a is a top View of both rotors;

FIGURE 9b is a top view of the top rotor with the bottom rotor shown in`dash lines; and

FIGURE 9c is a top view of the bottom rotor with the top rotor shown indash lines; and

FIGURES 10a through 10e are schematic representations of the air gapformed in the double rotor with the lower rotor being shown by dashlines. These views illustrate the manner in which the movable armaturecontact in the magnetic switches is transferred between pairs of fixedcontacts, and also the timing control of the armature contact by thedouble rotor. Further, these views illustrate the axial position of thesegments positioned on opposite sides of each magnetic switch withrespect to the grooves and tongues in the rotor.l v

Referring first to FIGURE l, a number of switching assemblies 16 through27 are positioned side by side and supported by a chassis 13 which maybe made of cast metal. Two flanges 13a and 13b on the sides of thechassis 13 engage slots 41 and 42, shown particularly in FIG- URES 2 and3, in each of the switching assemblies 16 through 27. The switchingassemblies 16 through 27 may be operated in synchronism by a motor 14which is coupled to the switching assemblies 16 through 27 by a gear box15. Two cables 31 and 32y provide for electrical connections to theswitching assemblies 16 through 27 and a cable 33 provides an electricalconnection to the motor 14. The bank of switching assemblies 16 throughZ7, the motor 14 and the gear box 15 may together have avweight of 32pounds and have overall dimensions of 5 by 6 by l5 inches.

The switching assemblies 16 through 27 may readily be removed from thebank or stack of assemblies by unscrewing a locking plate 67 which holdsa` circular plate 64- on a common shaft 46, and by sliding theassemblies along the flanges 13a and 13b of the `chassis 13. Asindicated above, each of the assemblies 16 through 27 may be ofidentical construction and the switching assembly 16 shown in FIGURES 2through 5 is illustrative. As shown in FIGURES 2 through 5, theswitching assembly 16 includes a stator 4G which is supported by meansof the grooves 41 and 42 on the anges 13a and 13b of the chassis 13, anda rotor 45 which is positioned concentrically in the stator `40. Thecommon shaft 46 extends through the rotor 45 and means not shown isprovided for -attaching the rotor 45 to the shaft 46 so that they rotatetogether. The attaching means may be in the form of a key, not shown,which must be removed in order to slide the rotor 45 off the commonshaft 46. When the switching assemb-lies 16 through 27 are stacked onthe chassis I3, the common shaft 46 extends through the rotor 45 of eachof the assemblies 16 through Z7. In effect, therefore, the rotors 45 ofeach of the switching assemblies 16 through 27 are mechanicallyconnected so that they all rotate as a unit.

The rotor 4d includes a number of magnetic switches 9) which areradially aligned about the rotor 4t). In the illustrative embodiment ofthis invention, there are 30 switches 90 in each of the switchingassemblies 16 through 27. With l2 assemblies 16 through 27 and 30magnetic switches 9d for each assembly, there are 12 times 30 or 360switches included in the stacked arrangement depicted in FIGURE l. Asillustrated in FIGURES 3 and 4, the thirty switches 90 of the assembly16 are pos-itioned between two permanent magnets 50 and 5I. The magnet541 is magnetized in one direction and the magnet 5l is magnetized inthe opposite direction. The internal portion of the magnet S9 adjacentto the rotor 40 may function as a south pole, and the internal portionof the magnet 51 adjacent the rotor 4t) may function as a north pole.

A ring 48, which may be made of magnetic material such as steel, isatiixed to the side of the magnet 51, and a ring 49, which is smallerthan the ring 48 is aixed to the magnet 51. The ring 49 may also be madeof magnetic material. The dimensions of the two rings 43 and 49 are suchthat when the assemblies 16 through 27 are stacked, the ring 48 of oneassembly fits over the ring 49 of the adjacent assembly. The minimumdiameter of the ring 4S is slightly larger than the maximum diameter ofthe ring 49.

The magnets 50 and 51 of adjacent assemblies are reversed so that thesimilarly polarized magnets in adjacent assemblies are positionedadjacent each other. More specifically, the lower portion of the magnet50 of one assembly at the left in FIGURE 4 is a north pole and also ofthe magnet 51 of the adjacent assembly at the right. The reason forreversing the magnets 50 and 51 in Iadjacent assemblies is to preventthe loss of magnetic flux to the stators 40 of adjacent assembliesinstead of providing it to the associated rotor 45 in the same assembly.If the magnets are not reversed in this magnet, some of the iiux fromthe north pole of the magnet 51 lin the assembly 1t) would pass throughthe ring 49 of the adjacent assembly 17 to the south pole of its magnet50. If a substantial non-magnetic gap is provided between the stators 4@of adjacent assemblies the magnets 50 and v51 in adjacent assemblies donot have to be reversed.

Between the two magnets 50 and 51 of the stator 40 are positioned anumber of cylindrical upper casing sections which may be made ofmagnetic material, such as steel. Each of the sections 79 encloses partof one of the magnetic switches 90. Each of the magnetic switches 90 issupported in the casing section 70 and also by the lower casing section91 which is made of non-magnetic material, Isuch as aluminum. Theportion of the section 91 adjacent to the rotor 45 is tapered and theswitch 90 is correspondingly tapered to t snugly therein. The twocasings 70 and 91 together form a cylindrical enclosure for the upperportion of the magnetic switch 90. The section 70 which is made ofmagnetic material forms a magnetic return path between the magnets 50and 51. 'Ihe section 91 is non-magnetic to avoid shunting any magneticux in the lower portion of the switch 9G to the magnetic return path atthe section 91. 'Ihe magnetic circuits through the stator 40 arehereinafter described in detail after the various components in therotor 45 are described.

The various components of the stator 40 including, the magnets 50 and51, the rings 48 and 49, the pairs of sections 70 and 91 and a number ofpairs of magnetic Segments 71 and 72, which are hereinafter described,are 4all glued together utilizing illustratively an epoxy resin. Thearrangement forms a highly compact and rigid structure. The switches 90,which are held in place by the non-magnetic sections 91 and the magneticsections 70, may readily be lremoved from the assembly 16 even when itis in the stacked arrangement illustrated in FIG- `URE 1. It istherefore unnecessary to decouple the assemblies 16 through 27 in orderto remove any of the switches 90 from any of the assemblies 16 through27. `Each of the magnetic switches 90, as is hereinafter described indetail, includes a lower portion or casing 113 and fan upper portion orcasing 112 (FIGURE 6) which is ysomewhat larger than the casing 113 andtapers Slightly towards it. Each of the lower casings 113 of themagnetic switches 90 extends into an annular air gap 95 formed in therotor 45. The annular air gap 95 is formed between two ring members 55and 56 which are made of a magnetic material, such as steel. The members55 and 56 are -supported by a central portion 45a of the rotor 45 whichis made of a non-magnetic material, such as aluminum. The two ringmembers 55 and 56 are continuous about the central portion 45a butprovide as is hereinafter described for some discontinuity. As the rotor45 rotates, the successive portions of the two ring members 55 and 56pass along opposite 'sides of the lower casings 113 of the magneticswitches 90.

The two magnets 50 and 51 in the stator 40 generate magnetic ieldsthrough the members 55 and 56 which control the operation of theswitches 90 as the rotor 45 rotates. The two ring members 55 and 56 areeach effectively double rings havin-g an upper ring and a lower ringwhich are contiguous and also concentric with each other. The member 55has an upper ring 55a and a lower ring 5512, as shown in FIGURES 9athrough 9c, and 10a through 10e, and the member 56 has an upper ring 56aand a lower ring 56h. The lower casing 113 of the switch 90 extends intothe gap formed by the double ring arrangement of the members 55 and 56.More specifically, the lower casing 113 extends between the two spacedapart rings 55a and 56a which have similar diameters yand also betweenthe two spaced apart rings' 55b and 5617. The two rings 5512 `and 56hhave similar diameters which are of course smaller than the diameters ofthe rings 55a and 56h.

The two upper rings 55a and 56a effectively form an upper or `top rotor61) and the two rings 55b and 56h form la bottom rotor 61. Thefunctional arrangement formed by the two ring members 55 and 56,accordingly, is that of a double rotor with each providing for differentiiux distortions in the magnetic circuit developed by the two magnets 5hand 51. The flux distortion introduced by the two ring members 55 and 56are somewhat different due to their different shapes which arehereinafter described in detail.

Though a number of reference designations have been mentioned relatingto the magnetic components of the rotor 45, there are actually only twomagnetic members and they vare the two bands or ring sections 55 :and56. The rotor shaft 46 of course may also be made of magnetic materialif so desired, because it is separated by the non-magnetic portion 45afrom the magnetic sections 55 and 56. rIihe various parts andcombination of parts of the sections 55 and 56 have been given referencedesignations to facilitate their ready identication and thereby anunderstanding of the operation of the rotor 45.

The upper ring 56a is cut back from the lannular air gap 95 whereas thelower rings 56h has a protruding annular flange extending towards theannular air gap 95. In FIGURE 4, this relationship: appears reversed butthe section depicted in FIGURE 4 is through the grooves and tongues ofthe double rotor arrangement. These grooves (55d and 56d) and tongues(55e and 56C) are hereinafter described. The shape of the double ringsections 55 is opposite to that of the double ring sections 56 with theupper ring 55a having a protruding annular flange extending towards theair `gap 95 and the lower ring 5511 being cut back from the air gap 95.Because of this symmetrical construction, the switches may be centrallypositioned in the air gap 95 at equal distances from the two sections 55and 56.

The upper surface of the ring 55a extends adjacent the steel segments 71which were briefly mentioned above. Each of the segments 71 is one of apair of segments 71 and "72 positioned at opposite sides of the switches90 and bridging the gap between the casings 113 and the sides of thering sections 55 and 56 forming the air gap 95. The segments 71 and 72which are made of conductive material such as steel, function tomaintain the reluctance of the magnetic circuits' through the stator 40and rotor 45 with variations in the axial position of the rotor 45. Thefunction of the segments 71 and 72 is further hereinafter described.

Due to the fact that the magnets 50 and 51 are supported in the `stator40, the ux pattern developed thereby is stationary. The two ring members55 and 56, which are positioned in the two magnetic circuits de velopedby the magnets 51 and 50, however, vary the ux paths as they rotate. Theupper ring 56a of the member 56 of the rotor 45 includes one or moretongues 56C (FIGURES 10a-10c) which extend along the steel segments 72and towards the annular air gap 95, and the ring 55a of the member 55includes one or more grooves 55d which are axially laligned with thetongues 56C to provide an air gap to the steel segments 71. The contourof the annular air gap is varied due to the presence of the tongue 56eand the groove 55d in the top rotor 60.

The bottom rotor 61 has an opposite conliguration. The ring 5611 has' agroove 56d directly under the tongue 56C of the ring 56a, and the ring55h has a tongue 55C directly under the groove 55d of the ring 55a. Thecircumferential width of the grooves 56d and 55d may be similar to otherand larger than the circumferential widths of the tongues 550 and 56C.The grooves 55d and 56d may illustratively be twice times as wide as thetongues 55C and 56C. FIGURES 9a through 9c illustrate theserelationships with FIGURE 9a showing both rotors 60 :and 61, FIGURE 9bshowing the top rotor 60 in Solid lines, and FIGURE 9c showing thebottom rotor 61 in solid lines. The tongues 55e and 56C mayillustratively be 1/16 of an inch wide, and the grooves 55d and 56d maybe ls of an inch wide.

The magnetic circuits through the rotor 45 are fairly complex because ofthe above-described rotor configuration and because of the presence ofthe segments 71 `and 72. Between the switches 9h about the periphery ofthe rotor d5 relatively high reluctance paths exist across the `air gap95. The steel segments 71 and 72 are only positioned at the switches 90.Though some magnetic flux is coupled across the air gap 95 between theswitches 90 most of it is coupled through the low reluctance pathsestablished by the one or the other of the segments 71 and 72 dependingupon the angular position of the rotor 45. When the groove 55d `and thetongue 56a .pass adjacent one of the switches 96 the switch 90 isoperated due to a change in the iiux coupled through the Switch 90.Normally the magnetic circuit is from the magnet 51 through the upperring 55a, a steel segment 71, through an armature in the casing 113 ofthe switch 90, the lower ring 56]), and the upper ring 56a to the magnet5t). The magnetic circuit is completed through the steel casing 90 backto the magnet 51. Throughout most of the circumference of the rotor 45,the magnetic circuit is through the upper ring 55a land the lower ring56h. At the tongue and grooves, however, the magnetic circuit reversesand is through the lower ring 55b and the' upper ring 56a.

The magnetic circuit is not normally through the lower ring 55b and theupper ring 56a because they are cut back and provide -for relativelylarge air gaps. The ring 551), being cut off provides for a large gap tothe casing 113, and the ring 56a, being cut back, provides for a largegap both to the casing 113 and to the segment 72. In this mannernormally a low reluctance circuit is provided through the segment 71 andhigh reluctance circuit is provided through the segment 72. The lowreluctance magnetic circuit is interrupted at the grooves 55d and 56dwhereas the higher reluctance circuit through the segments 72 becomes alow reluctance circuit at the tongues 55e and 55d. The low reluctancepath through the tongues 55C and 56o is from the magnet 51 through thetongue 55C of the lower ring 55]), the armature 115 of the switch 90,the segment 72, and the tongue 56C of the upper ring 56a to the magnet5d.

`As the rotor t rotates in the stator ttl, these contour variationsdefine changes in the reluctances of the magnetic circuits to producevariations in the magnetic forces on the armature `115 of the magneticswitches 90. Effectively, therefore, the tongues 55C and 56C and thegrooves 56d and 55d provide for a rotating flux pattern through theswitches 90. A magnetic armature 115 (FIGURE 6), hereinafter described,included in each of the switches 911 is moved as the tongues 55e and 56Cand the grooves 55d and 56d pass adjacent thereto. The tongues andgrooves, in this manner, provide for |an operating flux pulse which isrotated successively adjacent the switches 9@ in the switching assembly16.

The effect of the rotation of the rotor is particularly illustrated inFIGURES 10a through 10b. As shown in these FIGURES, as the rotor i5 ofthe switching assembly rotates toward the left, the Variation in thefluxy produced -by the tongues e and 56C and the grooves 55d and 56dapproaches the switch 90. The Switch 90l is stationary being supportedin the stator 40. As the tongues 55C and 56C move adjacent the switch90, as illustrated in FIGURE 10c, the movable armature 115 in the switchl90 is drawn from an upper to a lower ixed contact. The contacts areonly functionally depicted as actually the armature contact moves beingpairs of contactsegments. The segments (124-127) as well as the othercomponents forming the switch 9i) is hereinafter described. Thisoperation of the switch 911 is due to the fact that the tongues 55C and56C and the grooves 55d and 56d `change the air gaps from the rotor tothe armature 115 of the switch 9i). When the continued movement of therotor 45 moves the tongues 55C and 56C and the grooves 55d and 56d awayfrom the particular switch 90, the normal magnetic circuit isre-established to return the armature 115 to its original position. Asindicated in FIGURE 10e, the armature 115 of the switch 90 is moved backto its original position adjacent the upper fixed contact of the switch.

Therefore, each time the tongues 55e and 56C and the grooves 55d and 56dare swept adjacent one of the switches 90, the movable contact on thearmature of the switch 90 is first drawn out of engagement vtuth one setof ixed contacts and into engagement with another set `of xed contacts.The movable contact is subsequently returned into engagement with theone set of xed contacts and out of engagement with the other set offixed contacts. The switch 90 is in this manner pulsed each time thetongues 55C and 56e and grooves 55d and 56d pass adjacent thereto. Thissingle-pole, doublethrow action of each of the switches 91) is positivein both directions with the movable armature being no1'- mally held inengagement lwith the upper fixed contact and with it being moved by thetongues and grooves to the lower contact and then back again to theupper contact when the tongues and grooves pass. Y

The width of the grooves 55d and 56d, as described above and illustratedparticularly in FIGURES 10a through 10e, is twice the width of thetongues 55C and 56C. The greater groove widths provide for more rapidswitch operations. Thewidth of the steel segments 71 and 72 mayillustratively be 1/16 of an inch. The relative dimensions of thesegments 71 and 72, the grooves 55d and 56d and the tongues 55C and 56Care also depicted in FIGURES 10a through 10e. The dimensions are suchthat the segment 71 is fully adjacent the groove 55d in the upper ring55 before the segment 72 reaches the tongue 56e of the upper ring 56. Inthis manner the reluctance of the normal magnetic circuit is rstincreased, and the reluctance of the operative magnetic circuit isdecreased to operate the switch 90. The operation is sequential. Thenormal magnetic circuit as described above, is through the upper ring55a and the `lower ring 55h, whereas the operative magnetic circuit isthrough the lower ring 55h and the upper ring 56a. The magnetic iluxpath is in eiect twisted in a two step operation. In the first step themagnetic intensity in the segment 71 is reduced `and in the next stepthe magnetic intensity in the segment 72 is increased. The yforce on thearmature 115 of the switch 9d due to the flux through the segment 71 isin this manner fully halted before the force due to the flux through thesegment 72 is applied.

If the grooves and tongues are of the same width, a small delay occursdue to the necessity of dissipating the flux through the segment 71. Thearmature 115 remains in its normal position adjacent its upper contactsas the switch 911 moves into the area between the beginning of thegroove 55d and the beginning of the tongue 56C. This operation isfunctionally depicted in FIGURE 10b. Actually the switch is stationaryand the grooves 55d and 56d and the tongues 55C and 56C move to theleft.

In FIGURE 10c the tongue 56C is adjacent the switch 9@ and the armature115 is in its operative position. There is no counterforce due to iluxin the segment 71 because it has been fully dissipated. The transient orswitching interval for moving the armature is accordingly quite small,being measured in microseconds. In FIGURE 10d the tongue 56C has movedaway from the switch 90 is that the flux in the segment 72 dissipates.In FIGURE 10e, the switch 9i? is returned to normal as the extending lipof the ring 55 is now again adjacent' the segment 72.

In the particular illustrative embodiment of this invention, there maybe two sets of tongues and grooves in the rotor e5 so that each of theswitches 9i) is operated twice during each revolution of the rotor 45.The rotor 45 may be rotated at a speed of 20 revolutions per second `sothat each of the switches 90 is operated forty times each second witheach switch being operated during an similar in construction to theswitches disclosed in the copending patent application tiled on evendate herewith by Glenn A. Reese. A switch of this type is illustrated inFIGURE 6.

Referring to FIGURE 6, the magnetic switch 90 has an uppercylindrically-shaped shell 111 and 'a lower cylindrically-shaped shell112 together forming a casing for the magnetic switch 9i). The twoshells 111 and 112 Vhave substantially similar outer and inner diametersand may be of magnetic material such as steel to form a magnetic shieldfor the components enclosed therein. The shielding function of theshells 111 and 112 is hereinafter described. The two shells 111 and 112may be welded together to form a single composite cylindrical casing. Atone end of the magnetic shell 112 is affixed the armature casing 113which is preferably also cylindrical in shape and is adapted to befitted into the end of the shell 112. The armature casing or extension113 extends into the .annular air gap 95. The armature casing 113 isnonsmagnetic and may, for example, be of brass to permit magnetic fluxthrough the casing 113 to a hollow armature 115 enclosed thereby. Thearmature 115 is made of magnetic material such .as steel and ispreferably cylindrical in shape, being fitted in the armature casing113. An insulating collar 118 is mounted at one end of the armature 115for pivotable movement with the ,armature 115. The insulating collar 118has an outer diameter which is slightly greater than that of thearmature 115 and less than the inner diameter of the armature casing113.

rl`he armature 115 and the collar 11S are supported on a resilient wire116 which may be made of steel. The steel wire 116 is supported by aplug 117 which is tted at one end of the armature casing 113. The plug117 may be made of magnetic or nonmagnetic material and it may be madeof conductive or insulating material. The plug 117 need not be made ofinsulating material because, as is hereinafter described, the armature115 does not form part of the electric circuitry through the switch 90.The armature 113 is tilled with a viscous oil which forms a cushion forthe magnetic armature 115. A thin layer of oil is formed between theinsulating collar 118 and the inner surface of the .armature casing 113.This layer of oil forms a dynamic pivot for the magnetic armaturerelative to the armature casing 113 with the collar 113 functioning asthe fulcrum. As described above, the armature may be made of steel andthe collar 118 may be made of an insulating material. The collar 118 mayalso be made of a conductive material, as the armature 115 need not beinsulated from the armature casing 113 because it does not form a partof the electrical circuits through the switch 90. Though the collar 11Sand plug 117 may be made of conductive material, in the speciiicillustrative embodiment, these components are made of insulatingmaterial to reduce the coupling between the casing 113 and the activecomponents in the switch.

At one of its ends, the armature 115 supports the collar 113, and at itsother end it supports a contact insulator 120. The contact insulator 120is .a double plug member tting on one side into the hollow armature 115and on its other side into an armature contact 122 which is supportedthereby. The armature contact 122, which may be made of conductivematerial such as gold, is circular in cross section, but slight tapered(approximately a degree taper) away from the armature 115. Due to thecontact insulator 120, the armature contact 122 is insulated from thearmature 115.

The tapered armature contact 122 ts among, and is encircled by fourcontact segments 124 through 127 of a contact disc 123. The position ofthe armature contact 122 relative to the four segments 124 through 1217is illustrated particularly in FIGURE 8. In the normal position of thearmature 115, the contact 122 is in electrical contact with the twosegments 127 and 126 and, when the armature 115 is in its operatedcondition under the influence of the change in the magnetic eld throughthe casing 113, the contact 122 is in electrical contact with the twosegments 124 and 125. The stroke or movement of the contact 122 betweenthe pairs of segments may be quite small, illustratively 0.001 inch. Thespacing illustrated in FIGURE 8 is somewhat exaggerated to illustratethat the contact 122 is an electrical contact with only one pair of thefour segments 124 through -127 The length of the stroke may be adjustedwhen the switch is assembled by moving the armature 115 longitudinallyin the armature casing 113. Due to the taper of the armature contact122, its longitudinal movement with 10 respect to the disc 123 variesthe spacing between it and the segments 124 through 127.

The minimum distance between the two segments 125 and 127 issubstantially equal to the minimum distance between the two segments124r and 126 so that the armature contact 122 cannot simultaneouslyelectrically contact a pair of opposite segments. For example, thecontact 122 can never be simultaneously against the segment 125 and thesegment 127 because the distance therebetween is greater than thediameter of the armature contact 122 at its cross-section position inthe disc 123. This particular conliguration functions as a safetymeasure to prevent electrically connecting the two functional stationarycontacts of the switch 90 which are depicted in FIG- URES 10a to 10e.

The safety measure provided by the particular configuration of a disc123 and the armature contact 122 avoids establishing an electricalconnection between the two stationary contacts at any position of thearmature 122, even in the presence of shock or vibration of anymagnitude. The two stationary contacts can never be electricallyinterconnected because the diameter of the armature contact 122 at thedisc 123 is smaller than the distance between opposite pairs of thesegments of the disc 123.

The contact segments 124 through 127 may be gold plated and may beformed as one continuous disc 123 which is brazed on one end of aceramic insulator 130. The centrally located diamond shaped opening inthe disc 123 is formed by an accurate punch die before the disc 123 isaffixed to the insulator 130. After the disc 123 is brazed to theinsulator 130, the disc 123 and a portion of the ceramic insulator 130are cut to form the electrically isolated segments 124 through 127. Theceramic insulator 1130 may be cylindrically shaped having a maximumdiameter which is substantially the same as the maximum `diameter of thedisc 123. The ceramic insulator 130 has a small cylindrical opening 130aat the end to which the disc 123 is axed so that the armature contact122 can be inserted partially therein if necessary. The ceramicinsulator 130 lits snugly into the steel shells 111 and 112, which weredescribed above, having a maximum diameter slightly smaller than theinside diameters of the shells 111 and 112. When the ceramic insulator130' is manufactured, four cylindrical holes 140 are formed through theinsulator 130 having axes parallel to the longitudinal axis of theceramic insulator 130. The end of the ceramic insulator 130 adjacent thedisc 123 and the surfaces of the four holes are then metalized by aplating process.

When the disc 123 is cut to form the four segments 124 through 127, theend of the ceramic insulator 130 adjacent thereto is also cut to cut itsplated metallic surface. In this manner, the four segments 124 through127 are insulated from each other having no conductive connection acrossthe metallic surface on the end of the ceramic insulator 130. The fourcontact segments 124 through 127 are oriented on the ceramic insulator130 so that an electrically conductive connection is made from each ofthe segments 124 through 127 to one of the metalized holes 140 in theinsulator 130. At the other end of the four metalized holes 140 areinserted, respectively, four Wires 134 through 137 which provide forelectrical connections to the magnetic switch 90. The four wires 134through 137 extend through an opening 111a at the end of the steel shell111. In this manner, four electrical connections are providedrespectively through the four wires 1134 through 137, the four metalizedsurface holes 140 to the four segments 124 through 127 of the contactdisc 123.

The acute angle formed by the internal surface of either pair of twoadjacent segments maybe between 55 degrees and 60 degrees. Theparticular angle is selected to reing the angle acute, a slight skid isdeveloped by the armature Contact 122 as it wedges between the twoadjacent internal surfaces. lf the acute angle is made larger, thecontact 122 hits the segment surfaces with a smaller skidding effect sothat any tendency to bounce is increased. The more closely is thecontacted segment surface aligned to be perpendicular to the directionof motion of the contact 122, the greater the bounce. Bounce is harmfulbecause of the noise it introduces and because the timing of the switch90 becomes less accurate. By providing for an acute angle between theinternal surfaces of the segments 124 and 125, the contact 122 wedgestherebetween as it is moved on the armature 115 so that any tendency tobounce is resisted.

In order to maintain the timing accuracy of the switch, there is apractical lower limit to the size of the acute angle formed by theadjacent internal surfaces of the segment pairs. As the acute angle ismade smaller, the tolerances for the contact swing become greaterbecause it is more dificult to predict the exact point on the internalsurface which will first engage the contact 122. By making the anglemore acute, the dimension of the internal surface in the direction ofthe contact swing is greater and a small eccentricity in the contactswing varies the duration of the switching operation by a considerablefactor. With a stroke of 0.001 inch gives an illustration above, theswitching interval responsive to a change of the magnetic ux through thearmature 115 may be approximately 200 microseconds. The moreperpendicular are the alignments of the contacted internal surfaces withthe direction of the movement of the contact 122, the less variation inthe switching interval and, therefore, the more accura.e the timingprovided by the switch 90. The particular angle which is selected is,therefore, a compromise to both reduce bounce and maintain smalltolerances in the timing of the switch 90.

Noise pulses are not readily introduced by capacitive or electricalcoupling to the armature 115 because it is electrically insulated fromthe electrical circuits through the switch 90. The contact insulator 120prevents any electrical disturbances introduced to the armature 115either by capacitive coupling with the casing 113 or by electricalcontact therewith from being introduced to the segments 124 through 127of the contact disc 123. With the armature 115 isolated in this mannerfrom the electrical circuitry, a noise level illustratively as small asl microvolts is present. The l0 microvolt illustrative noise levelrepresents the total noise level due to all factors including due tobounce and stray capacity. Signals, for example, as low as 20 microvoltsmay accordingly be switched by the switch 90 and readily separated fromthe noise.

In the switch 90 illustrated in FIGURE 6 and described above, thearmature 115 is pivoted at the collar. FIG- URE 7 depicts anotherembodiment of a magnetic switch, which embodiment is particularlysuitable for use as part of the switching assembly 16. Referring now toFIG- URE 7, a switch 190 is shown which is similar to the switch 90shown in FIGURE 6. The various similar components have similar referencedesignations with the addition of 100. The armature 115 in FIGURE 6 has6 a corresponding armature 21S in FIGURE 7. The armature 115 is.supported on a wire 216 in the lower casing 213. The armature contact222 is movable between the segments of the disc 223. The operation ofthe switch 190 is exactly the s-ame as that of the switch 90v exceptthat the armature is pivoted at its center instead of at its lower end.

The armature 215 is pivoted on a ring 218 supported by the lower casing213. The central pivoting operation is particularly suited to the doublerotor construction because as illustrated in FIGURE 4 and describedabove, the operative magnetic circuit is through the ktongue .55e of thelower ring 55h, through the armature to the segment 72 and to the tongue56C of the upper ring 56a. When the tongues 55e and 56C come adjacentthe casing 213, the lower end of the armature 215 is pulled towards thetongue 55e and the upper end of the armature 215 is pulled towards thetongue 56e. The forces are applied in this manner at the ends of thearmature 215. By pivotally balancing the armature 215 at its centerthese forces are more elfective to move the armature 215 quickly to itsoperative position. Moreover as is hereinafter described, centrallybalancing the armature assists in maintaining the timing accuracy of theswitch with variations in the axial position of the rotor 45.

In the rest of the description of the operation of the assembly and inthe preceding description, each reference to a switch is also intendedto refer to the switch 190' as either can be used in the assembly 16.

Any displacement of the rotor 40 longitudinally along its axis ofrotation tends to vary the timing of the operation of the switches 90.Both the double rotor construction and the -steel segments 71 and 72maintain the timing accuracy with axial movements of the rotor 45. Forexample, in the absence of a double rotor construction and the segments71 and 72, one 10,000ths of an inch axial movement of the rotor 45provides for a variation of plus or minus 400 microseconds for a 1750microsecond channel. As indicated above, the switches 90 are operatedsuccessively during the 1,750 rnicrosecond intervals. A variation ofplus or minus 400 microseconds provides for a considerable error in theoperating duration of the switches 90. The double rotor construction andthe segments 71 and 72 reduce this error considerably and in `factgreater axial movements, for example as large as 0.0250 inch producenegligible timing variations. When the double rotor, and the segments 71and 72 are utilized Iall timing aspects of the switch assembly operationremain substantially constant with axial movement of the rotor 45. Forexample, the switching interval, and the operating duration of eachofthe switches 90 is substantially constant.

The steel segments 71 and 72, which are positioned on opposite sides ofeach of the switches 90, reduce the timing variations because the ux tothe switches 90 is actually through one or the `other of the steelsegments 71 and 72 instead of directly only from the rotor steel rings55 and 56. As shown particularly in FIGURES 3 and 4, the steel segments71 and 72 are tapered so that the iiux into the segments 71 are directedinto the lower tubular casing 113 of the associated switches 90, and theflux from the segment 72 is directed to the tongue 56e. The steel-segments 71 and 72 are positioned over the steel rings 55 and 56 of therotor 45 independent of its axial position. The flux change at thetongue 56C and the groove 55d is effective at the respective instantsthey pass adjacent the segments 71 and 72. The exact instant therespective uxes change does not depend upon the exact axial position ofthe rotor 45, and the magnitude of the flux change also does not dependupon the exact axial position of the rotor 45 because the segments 71and 72 bridge the gap to the switch 90 irrespective of the axialposition of the rotor 45.

Though the axial position of the rotor '45 varies the reluctance of themagnetic path from each of the steel rings 55 and 56 directly to thecasing 113 of the switch 90, it does not vary the reluctance of the paththrough either of the segments 71 and 72 to the casing 113 of the switch90. In effect, due to the low reluctance of the segments 71 and 72, theydistribute the flux from the associated rings 55 and 56 and act aspulses for the switch 90. As the rotor 45 rotates, the flux variationdue to the tongues and the grooves accordingly energizes the successivepairs of segments 71 and 72 to pulse their associated switches 30. Dueto the segments 71 and 72, the timing accuracy is maintained even withsmall axial movements of the rotor 45.

As indicated above, the timing accuracy is maintained in the presence ofaxial rotor movement because of the double rotor construction as well asbecause of the presence ofthe steel segments 71 and 72. The operativemagnetic circuit, which is depicted in FIG. 4, is through the lower ring55h, an air gap to the armature 115 in the casing 113, through thearmature 115 and to the steel segment 72 to the upper ring 56a. Due tothe proximity of the tongue 56e in the ring '56a to the armature 115,some magnetix fiux passes from the armature 115 across the small air gap4to the tongue 56C. There are therefore two small air gaps in theoperative magnetic circuit: one from the tongue 55C to the anmature 115;and the other from the armature 1115 to the tongue 56C. Any axialmovement of the rotor 45 increases one of these air gaps and decreasesthe other so that the total reluctance of the magnetic circuit remainsapproximately constant.

The utilization of a double rotor construction with two tongues 55C and56o in the operative magnetic circuit and two air gaps, provides forcounteracting reluctance changes 'responsive to an axial variance in theposition of the rotor 45. Because of the double rotor operation and thebridging function of the pairs of segments 71 and 72 the timing of theswitches is very accurate.

When the switch 190 (FIGURE 7) is utilized the forces developed at theopposite ends of the armature 215 are both operative in moving thearmature 215. If 4a centrally pivoted armature 215 is utilized, anyaxial movement of the rotor `45 which tends to decrease the force at oneend of the armature would tend to increase it at the other end so thatthe total torque on the armature 215 remains constant.

The timing `accuracy is maintained even if the armature 115 (or 215) isnext exactly centered in the casing 113 lbecause any variation of itsalignments produces counteracting reluctance changes in the operativemagnetic circuit. The tolerances of the switch 90 construction mayaccordingly be less critical when the double rotor construction isutilized Without eecting the timing accuracy. Moreover, the switches 90need not be accurately aligned in the air gap. For example, ifpositioned even at angles of 15 degrees `from accurate alignment, thetiming accuracy of the operation is maintained.

Although this application has been disclosed and illustrated withreference to particular applications, the principles involved aresusceptible of numerous other applications which will be apparent -topersons skilled in the art. For example, the number `of switches 90 may'be more or less than 30, and the sets of tongues yand grooves may bemore or less than 2. The invention is, therefore, to be limited only asindicated by the scope of the appended claims.

We claim:

1. A magnetically controlled switching assembly including, meansrotatable on a particular axis and having first and second walls spacedto define a continuous annular air gap between the walls, said wallsbeing made of `a magnetic material and having contours to define firstand second displacements at radially displaced positions in the lair gapin at least one position circumferentially along the walls, stationarymagnetic means magnetically coupled to said rotatable means forproducing a magnetic iield in the air gap in accordance with thecontours of the walls defining the air gap, switching means transverselydisposed with respect to the axis of rotation of said rotatable meansand also having two operating conditions, said switching means beingdisposed relative to the air gap of said rotatable means and responsiveto variations in the magnetic field to be :actuated from one operatingcondition to the other, and means coupled to said rotatable means lforrotating said rotatable means to move said Walls adjacent said switchingmeans to periodically bring said switching means under the influence ofthe variations in the magnetic field.

2. A magnetically controlled switching assembly including: a rotorrotatable `on a particular axis and including first and second wallsspaced to define a continuous air gap between the walls and providedwith contours in at least one wall to define first and seconddisplacements in said air gap at radially displaced positions in thedirection between the walls, magnetic means coupled to said rotor forproducing in the air gap a magnetic flux having uniform characteristicsat successive positions in the air gap and exhibiting variations incharacteristics at the position of displacement and in accordance withsuch displacement, and at least one switching unit having rst and secondswitch contacts electrically and magnetically isolated from the casingand movable relative to each other and having an armature coupled to aparticular one of the switch contacts and in spaced relationship to theother contact and responsive to the variations in the magnetic flux toproduce a relative movement of the particular contact into engagementwith the other contact, means for supporting the switching unit toextend into the air gapy in a direction perpendicular to the axis ofrotation of said rotor with the armature disposed in the air gap torespond to the variations in the magnetic flux in the air gap due to theupper and lower displacements of said one Wall, and means for rotatingsaid rotor to produce periodic actuations of the switching unit.

3. A switching assembly, including, a rotor rotatable on a particularaxis and including a first set of spaced rings of magnetic materialdefining between the rings a first continuous air gap having contours todefine a displacement in the air gap in at least one circumferentialposition of the rings, the rotor further including a second Set ofspaced rings radially positioned with respect to said first set andbeing made of magnetic material and defining therebetween a secondcontinuous air gap continuous with the first continuous air gap, saidair gap defined by the rings of said second set having contours todefine a displacement in at least one axial position relative to the airgaps defined by rings of said first set; stationary magnetic meansdisposed relative to said rotor for producing in said air gap a fieldexhibiting Variations at the position of the displacements; switchingmeans extending into said air gap and transversely disposed with respectto the axis of rotation of said rotor, said switching means having firstand second operating conditions and being responsive to the variationsin said field to be actuated from the first operating condition to thesecond operating condition; and means coupled to said rotor for rotatingsaid rings to bring `said switching means periodically under theinfiuence of the variations in the field.

4. A switching assembly, including, a rotor rotatable on a firstparticular axis and including a first set of spaced rings of magneticmaterial defining between the rings a continuous air gap having contoursto define a displacement in the air gap in at least one circumferentialposition of the rings, the rotor further including a second set ofspaced rings of magnetic material radially displaced from the rings ofsaid first set, said rings of said second set defining therebetween acontinuous air gap continuous with the air gap defined by the rings insaid first set, said rings in said second set defining an axialdisplacement in the air gap therebetween at a circumferential positioncorresponding to the displacement of the air gap defined by the rings insaid first set, the displacement of the air gap defined by the rings insaid second set being different than the displacement of the air gapdefined by the rings in said rst set, stationary magnetic means disposedrelative to said rotor for producing in said air gap a field exhibitingvariations at the circumferential position of the displacements,switching means extending into said air gap and transversely disposedwith respect to the axis of rotation of said rotor, said switching meanshaving first and second operating conditions and being responsive to thevariations in said field to be actuated from the first operatingcondition to the second operating condition, and means coupled to saidrotor `for rotating said rings to bring said switching meansperiodically under the influence of the variations in the field.

rl a.

5. A switching assembly, including, rotary means having a pair ofconcentric rotors of magnetic material together defining a continuousannular air gap having a pair of radially displaced contours in the airgap at corresponding positions of the two rotors, means magneticallycoupled to the pair of rotors for producing in said air gap a fieldexhibiting variations at lche position of the radially displacedcontours, switching means extending into said air gap and transverselydisposed with respect to the axis of rotation of said rotor, saidswitching means having first and second operating conditions and beingresponsive to the variations in said field to be actuated from the firstoperating condition to the second operating condition; and means coupledto said rotary means for rotating said rotary means to bring saidswitching means periodically under the influence of the variations inthe field.

6. A switching assembly in accordance with claim wherein each of saidconcentric rotors has a tongue extending into said annular air gap todefine the displacements in said annular air gap, said extensions of thetwo concentric rotors being on opposite axial sides of said annular airgap.

7. A switching assembly, including, a rotor having a first set of twospaced apart rings of magnetic material defining between the two rings acontinuous annular air gap, one of said rings having at least oneperipheral groove, the other of said two rings having at least oneperipheral groove, the other of said two rings having an extension ofmagnetic material extending into said annular air gap opposite to saidgroove in said one ring, and a second set of two spaced apart rings ofmagnetic material defining between them a continuous air gap which isconcentric and contiguous with the air gap defined between the two ringsof the first set, one of said rings of said second set having at leastone peripheral groove, the other of said two rings of said second sethaving an extension of magnetic material extending into said air gapdefined by said second set and opposite to said groove in said one ringof said second set, at least one magnetic switch radially aligned withrespect to the axis of rotation of said rotor and extending into saidannular air gaps between the two rings of both said first and saidsecond sets, means having properties -to produce a magnetic fieldthrough the two rings of both said first and said second sets exhibitingvariations at their peripheral grooves and extensions, and means coupledto said rotor for rotating said rotor to effectively rotate thevariations in magnetic field successively adjacent said radially alignedmagnetic switch, said radiallyaligned magnetic switch having twooperating conditions and being responsive to the variations in themagnetic field to be actuated from one condition to the other.

8. A switching assembly in accordance with claim 7 wherein said ring ofsaid one set having a peripheral groove is concentrically positionedwith respect to said ring of said second set having the extension ofmagnetic material so that they are aligned along a radial line from thecenter of the rotor.

9. A switching assembly in accordance with claim V7 wherein saidperipheral grooves in both said first and said second sets havecircumferential lengths greater than the circumferential lengths of theextensions in both said first and said second sets.

l0. A switching assembly, including, a rotor having a first set of twospaced apart rings of magnetic material defining between the two rings acontinuous annular air gap, one of said rings having at least oneperipheral groove, the other of vsaid two rings having at least oneperipheral groove, the other of said Vtwo rings having an extension ofmagnetic material extending into said annular air gap opposite to saidgroove in said one ring, and a second set of two spaced apart rings ofmagnetic material defining between them a continuous air gap which isconcentric and contiguous with the air gap defined between the two ringsof the first set, one of said rings of said second set having at leastone peripheral groove, the other of said two rings of said second sethaving an extension of magnetic material extending into said air gapdefined by said second set and opposite to said groove in said one ringof said second set, at least one magnetic switch radially aligned withrespect to the axis of rotation of said rotor and extending into saidannular air gaps between the two rings of both said first and saidsecond sets, means having properties to produce a magnetic field throughthe two rings of both said first and said second sets exhibitingvariations at their peripheral grooves and extensions, means coupled tosaid rotor for rotating said rotor to effectively rotate the variationsin the magnetic field successively adjacent said radially alignedmagnetic switch, said radially aligned magnetic switch having twooperating conditions and being responsive to the variations in themagnetic field to be actuated from one condition to the other, and twomembers of magnetic material positioned on opposite sides of saidmagnetic switch and extending respectively adjacent the peripheralsurfaces of said two rings of said one set for providing low reluctancepaths to said switch whereby the strength of the magnetic field at saidswitch does not depend upon the exact axial position of said rotor.

1l. A switching assembly, including, means rotatable on a particularaxis and including first and second walls spaced to define a continuousair gap between the walls and having contours to define displacements insaid air gap along one portion of said walls, said displacements beingin the form of grooves in the walls and extensions from the walls, witheach of said first and said second walls including Vone groove and oneextension radially displaced from the groove and with the groove in eachwall being adjacent the extension on the other wall, switching meansdisposed partially in said air gap and transversely disposed withrespect to the axis of rotation of said rotatable means, said switchingmeans having first and second .operating conditions and being responsiveto the variations in said field to be actuated from the first operatingcondition to the second operating condition, and means coupled to saidrotatable means for producing relative motion between said walls andsaid switching means to bring said switching means periodically underthe infiuence of the variations in the field in accordance with themovements of said grooves and extensions of said first and said secondwalls past said switching means. i

l2. A switching assembly in accordance with Vclaim ll wherein each vofsaid grooves has a circumferential length greater than thecircumferential length of each of said extensions, and wherein saidgroove of said rst wall is at a greater radial distance from the axis ofrotation of said rotatable means than lis said extension of said firstwall, and said groove of said second wall lis at a smaller radialdistance from the axis of rotation of said rotatable means than is theextension of said second wall.

13. A switching assembly, including, means rotatable on a firstparticular axis and including first and second walls spaced to define acontinuous air gap between the walls and .having contours to definedisplacements in said air gap along one portion of said walls, saiddisplacements being in the form of grooves in the walls and extensionsfrom the walls, with each of said first and said second .walls includingone groove and one extension radially displaced from the groove with thegroove in .each wall being adjacent the extension in the vother wall,switching means extending said air gap and transversely disposed withrespect to the axis of rotation of said rotatable means, said switchingmeans having first and second operating conditions and being responsiveto the variations in said field to be actuated from the rst operatingcondition to the second operating condition, means coupled to saidrotatable means for producing relative motion between said walls andsaid switching means to bring said switching means periodically underthe influence of the variations in the tield in accordance with themovements of the grooves and extensions of said first and said secondwalls past the switching means, and segment members magnetically coupledto said elongate switching means and positioned at opposite sides ofsaid switching means and spanning said air gap to inhibit axialmovements of said rotatable means from affecting the timing accuracy ofthe switching assembly.

14. A magnetically controlled switching assembly, including, a rotorrotatable on a particular axis and having first and second walls spacedto dene a continuous air gapy between the walls, said walls being madeof a magnetic material and having contours to define first and secondaxial displacements in the air gap along the walls, the first axialdisplacement of the first wall and the second axial displacement of thesecond Wall being grooves, and the second `axial displacement of thefirst wall and the first axial displacement of the second wall beingtongues extending toward the grooves, stationary magnetic meansmagnetically coupled to said rotatable means for producing a magneticfield in the air gap having variations in accordance with thedisposition of the tongues and grooves in the walls defining the airgap, switching means extending into the air gap and transverselydisposed with respect to the axis of rotation of said rotatable meansand having first and -second operating conditions, said switching meansbeing responsive to variations in the magnetic field to be actuated-from one operating condition to the other, and means coupled to saidrotatable means for rotating said rotatable means to move said wallsadjacent said switching means to bring said switching means under theinfiuence of the variations in the magnetic field.

l5. A switching assembly, including a rotor rotatable on a particularaxis and including a lfirst set of spaced rings of magnetic materialdefining between the two rings a continuous annular air gap, one of saidrings havin-g at least one peripheral groove, the other of said tworings having a tongue extending into said annular air gap opposite tosaid groove in said one ring, the rotor also including a second set ofspaced rings of magnetic material defining between them a continuous airgap which is continuous with and radially displaced from the air gapdefined between the two rings of the first set, one of said rin-gs ofsaid second set having at least one peripheral groove, the other of saidtwo rings of said second set having a tongue extending into said air gapdefined by said second set and opposite to said groove in said one ringof said second set, at least one magnetic switch transversely disposedwith respect to the axis of rotation of said rotor and extending intosaid annular air gaps between the rings of both said first and saidsecond sets, means producing magnetic fields through the rings of saidfirst and said second sets and producing variations in the magneticfields at the peripheral grooves and tongues, and means coupled to saidrotor for rotating said rotor to obtain rotary movements of the varia-18 tions in magnetic field past said magnetic switch, said magneticswitch having first and second operating conditions and being responsiveto the variations in the magnetic field to be actuated from the firstoperating condition to the second operating condition.

16. A switching assembly in accordance with claim l5 wherein theperipheral groove of said ring of said one set is concentricallypositioned wtih respect to the tongue on said ring of said second set sothat they are aligned along a radial line from the center of the rotor.

17. A -switching -assembly in accordance with claim 15 wherein saidperipheral groove in the ring of each of said first and said second setshas a circumferential length greater than the circumferential length ofthe tongue in the ring of each of said first and said second sets.

18. A switching assembly in accordance with claim 15 wherein the ringhaving the peripheral groove in each of the first and second sets isdisposed radially at a position corresponding to the ring having thetongue in the other of the first and second sets.

19. A switching assembly, including, a rotor rotatable on a particularaxis and including a first set of spaced rings of magnetic materialdefining between the rings a continuous annular air gap, one of saidrings having at least one peripheral groove, the other of said ringshaving a tongue extending into said annular air gap opposite to saidgroove in said one ring, the rotor also including a second set of spacedrings of magnetic material defining between them a continuous air gapwhich is continuous with and radially displaced from the air gap definedbetween the rings of the rst set, one of said rings of said second sethaving at least one peripheral groove, the other of said rings of saidsecond set having a tongue extending into said air gap defined by saidsecond set and opposite to said groove in said one ring of said secondset, at least one magnetic switch disposed transversely with respect tothe axis of rotation of said rotor and extending into said annular airgaps between the rin-gs of said `first and `said second sets, meanshaving properties to produce magnetic fields between the rings of saidfirst `and said second sets wherein the magnetic fields exhibitvariations at the peripheral grooves and tongues in the rings of thefirst and second sets, means coupled to said rotor for rotating saidrotor to obtain movements in the variations in the magnetic field pastsaid magnetic switch, said magnetic switch having first and secondoperating conditions and `being responsive to the variations in themagnetic field to be actuated from the first operating condition to the4second operating condition, and a pair of members of magnetic materialpositioned on opposite sides of said magnetic switch and -extendingrespectively adjacent the peripheral surfaces References Cited in thefile of this patent UNITED STATES PATENTS Reese Apr. l2, 1960 Reese`luly 19, 1960

